"It is a law of human nature," David Brooks writes in his newest book The Social Animal, "that the more men you concentrate in one happy pack, the more each of them will come to resemble Donald Trump. They possess a sort of masculine photosynthesis to start with — the ability to turn sunlight into self-admiration. By the law of compound egotism, they create this self-reinforcing vortex of smugness, which brings out the most-pleased-with-themselves aspects of their own personalities."

What makes The Social Animal the most satisfying and important book I've read in a very long time is that Brooks so brilliantly and evocatively explains why we've gone so far off course in this country, attributing it not to bad policies but to human failings we haven't begun to recognize, much less acknowledge.

Brooks' core argument is that the vast majority of us have very little understanding of why we make the choices we do, and that we're influenced instead by peer pressure; impulsive and reactive emotions; a deep and bottomless need for admiration and status; overconfidence in the present; excessive worry about the future; the evolutionary instinct to avoid pain and move towards pleasure; and precious little capacity to delay gratification.

"The unconscious parts of the mind are most of the mind," Brooks writes, "[with] a processing capacity 200,000 times greater than the conscious mind." Tragically, this interior domain remains largely terra incognita, a vast unexplored territory full of resources and potentials we haven't begun to tame or to tap.

Instead of drawing on our rational faculties to more deeply understand our interior impulses and motivations, we too often use our prefrontal cortex to rationalize, justify, minimize and explain away the unconsciously driven actions we've already taken. "A man hears what he wants to hear," Paul Simon sings in The Boxer, "and disregards the rest."

In short, we have an infinite capacity for self-deception. Or, as Brooks puts it, "People overestimate their ability to understand why they are making certain decisions. They make up stories to explain their own actions even when they have no clue about what is happening inside."

Worse yet, the most powerful among us have a tendency to bloviating certainty — swatting away doubt and choosing up sides precisely because not having answers feels so uncomfortable and potentially threatening. Opinions, in turn, become polarized and rigid. Just consider the current budget negotiations, marked as they are by a blatant disregard for logic and a perilous potential cost to the greater good.

What Brooks argues for, and embodies in his writing, is something he calls "epistemological modesty" — substituting humility for hubris. Epistemology is the study of how we know what we know. Modesty is warranted, Brooks argues, because there is so much of ourselves we don't and can't know. "People with this disposition believe that wisdom begins with an awareness of our own ignorance," he explains.

I've read Brooks' op-ed columns in The New York Times for years, but it was only with this book that I understood what sets him apart from his journalistic colleagues. It's his unwavering willingness to grapple with issues rather than simply pontificate about them; to embrace nuance, ambiguity and paradox rather than choosing up sides; and to be forever open to learning and to being changed by what he learns.

What Brooks lays out in The Social Animal is a path to a more meaningful life — one that balances action with introspection, confidence with restraint.

Describing the person who aspires to such a life, Brooks is transparently autobiographical when he writes, "He (tries) to remind himself of how little we know and can know, how much our own desire for power and to do good blinds us to our own limitations. He pays attention to the sensations that come up from below. He makes tentative generalizes and analyses ... He continues to wander and absorb, letting the information marinate deep inside."

I also learned from reading this book why I can't possibly assess it objectively. Each of us, he argues, consciously and unconsciously seek out people in life whose values, opinions and sensibility most mirror our own. It's humbling to recognize that I delighted in his writing at least in part because it so persuasively and stylishly confirms much of my own world view. If you resonate with what I've written, it probably confirmed a lot of yours, too.

Tony Schwartz is the CEO and founder of The Energy Project and bestselling author of The Way We're Working Isn't Working. A frequent keynote speaker, Tony has also trained and coached CEOs and senior leaders at organizations including Apple, Google, the LAPD, and the Cleveland Clinic.